whyte



May 28, 1940. c, WHY-r5 Re. 21,471

COLORING OF BEN? WOOD PRODUCTS Orizinal Filed May 25. 193'? INVENTOR. Wm C WHYTE BY A A TTORNEY Reissued May 28, 1940 UNITED STATES PATENTOFFICE COLORING 0F BENT WOOD PRODUCTS Original No. 2,147,587, datedFebruary 14, 1939,

Serial No. 144,600, May 25, 1937.

Application for reissue March 27, 1940, Serial No. 326,301

9 Claims. (Cl. 273-43) This invention relates to improved artificiallycolored articles comprising tenacious, brilliantly dyed hardwoods andmore especially as applied to bent tennis racket frames, snow shoes,skis, trout landing net hoops or the like set shapes of arcuate contour.My dyed wood may be penetrated in a uniformly diffused manner to afforda substantially bright appearance throughout the frame body and toimpart an attractive, durable and non-streaky surface finish theretothat shall not peel or scruff off.

The harmful effects resulting from the successive hot dyeing, bendingand forced drying of such wood products may be minimized by consistentlyrestricting the temperature intensity and by fixing upon the allowabletotal heat treating time required to complete all operations thereon.The present improvements strive to so control the necessary combinedtreating steps as to substantially obviate their accumulativedetrimental heating effects upon a finished bent wood product,particularly as regards its shock absorbing property against impactloading. In addition, my hot dyeing treatment to some extent improvesthe properties of a bent laminated racket in that augmented. framerigidity and hardness are imparted thereto over its original plywoodstock.

The same dyeing procedure admits of fabricating a hoop shaped frame froma single or different specie of laminated wood in which the respectiveouter or inner plies prior to gluing, may be dyed in spectral hues in acontrasting or harmonizing color scheme to heighten its decorativeappearance as a distinctive marketable commodity over the correspondinguse of woods in natural colors. Both the solid and laminated types ofartificially colored racket frames are made to preserve adequate tensilestrength and other inherent qualities by resorting to a suitable primarygrade of wood that will effectively meet over a prolonged period ofusage, the arduous requirements of a batlike ball striking implementwithout latent flaws or superficial discoloration.

The preferred grade of hardwood to be ,employed in the fabrication of mydyed racket frame or the like, is second growth, commercial white ash,particularly its selected straight-grained or clear sapwood which may bemade to preserve its inherent strength when properly heat treated.

3 The grain of all bent plies properly extends in a direction lengthwiseof the hoop contour. Said stock also affords the required initial ornatural pale base into which to uniformly impregnate any desired brightcoloring matter,preferably certain kinds of water soluble, organicdyestuffs of an extremely soluble character, since apparently not all ofthe so-called anilin or the like synthetic dyes react in the mannerherein contemplated. The cited white sapwood of ash ranks relativelyhigh in specific gravity, tensile strength, toughness against impactloading, bends flawlessly in relatively thick plies, and retains its setshape to a marked degree after being bent to form.

The fact'that such wood does possess a low volumetric shrinkage from agreen state into an oven dried condition, together with its relativelysmall natural moisture content, assumes significanoe in restricting thetendency to swell, to straighten out with increased moisture absorption,or otherwise alter the original arcuate shape of a bent frame whensubjected in use to an anticipated rather wide degree of change inatmospheric humidity.

A varnished, painted or shallow stained surface finish for a tennisracket frame or the like is susceptible to weather conditions and itsinherent color frailty may ultimately lead to an unsightly, wornappearance. Such superficially applied coatings tend to disintegratewith age by cracking or flaking especially as regards the swingingarched head of a tennis racket which is likely to suffer rapid abrasionin active service. By virtue of a uniform dye impregnation, my framehead will not reveal a different underlying color, although subjected tosevere knocks or long repeated ground scraping. A shaped up product ofthis kind may also during its manufacture, be deeply shaved on andsanded without change in color.

Furthermore, tennis racket frames and the handles thereof not only callfor ample inherent strength, but should nicely be held to a definitebody size to provide for the requisite heft and resulting fine balancedfeel that will wholly satisfy professional playing needs.

In order to realize the maximum break down capacity in a bent laminatedracket frame, it is expedient to provide for a high degree oflongitudinal shear resistance in each component ply thereof. Inaccordance with conventional decorative practice, a soft wood inlay iscommonly inserted between stronger ash plies in their respective naturalcolors. An interposed lamination of this species possesses a low shearstrength and hence is likely to correspondingly weaken a completedlaminated frame. Under break down bending tests, many of suchconventional inlays have been found to fail from lengthwise grain shearbetween the glued ply faces thereof. By resort to a dyed wood inlaypossessing a markedly higher inherent shear property, it becomespossible by dyeing, to obtain a far wider color selection together withincreased strength at a materially lowered fabrication cost, thereby notonly more effectively utilizing cheaper grades of American woods such aswhite ash, but at the same time obviating the cited grain shear frailtyon part of a conventional softer inlay.

In addition, my inner and outer frame plies may without harmful resultsbe dyed to a color that sharply contrasts with their inlays. Woods thatpresent a sharply defined natural color, seldom afford a straight graincleavage and when attempt is made to use such weaker woods as a heavyreenforcing outer ply, they frequently fracture upon being closely bentto the required shape. The instant innovations pertain to the refinedfabrication of a high grade racket frame without allowing its decorativepattern to wear off under prolonged usage.

The fabricating of a tennis racket that shall prove acceptable toexperienced players by satisfactory performance, is a difficult art.Present day bent wood tennis frames are required to possess in highdegree, appropriate qualities that can only be attained by selecting themost suitable wood species. Any substantial deviation from this exactingstandard has generally been found unacceptable to the trade, it beingemphasi'zed that a proportionate drop of less than one-half of themaximum attainable break down strength of a conventional all-ash racket,is likely to result in its complete commercial rejection.

The instant ball impelling frame is preferably dyed prior to the moistbending thereof into a required hoop or other arcuate shape, whereuponthe partially treated article may be subjected to intensified or ovendrying to remove surplus moisture at a comparatively rapid rate. Anypermanent injury resulting from such forced drying or discoloration intoa comparatively dark shade of the frame stock, may be materiallymitigated by a careful control of the temperature elevation of the dyebath and drying oven by definitely restricting the total time duringwhich any high temperature is applied, the heat treatment in itsentirety being herein deliberately terminated prior to permitting theresidual bending strength of the treated wood to become inordinatelylowered or allowing a brilliant spectral color to become vitiated.

The primary object of the present invention is to fabricate a neatlytrimmed, decorative racket frame or the like bent shape of either solidor plywood that is dye impregnated in one or more artificially coloredbase woods, the goal being to generally work for the optimum as regardsthe application of a durable brilliant pattern or other pleasing colorscheme to such wooden structure and thereby provide against superficialdiscoloration under prolonged hard usage and its resulting wear.

Reference is had to the accompanying one sheet of drawings in which:

Figs. 1 and 2 respectively represent a face and an edge view of a tennisracket treated and equipped in accordance with my invention.

Fig. 3 is a cross-sectional view of a solid racket frame as taken alongline 33 of Fig. 1.

Fig. 4 is similar to Fig. 3 but illustrates a laminated in lieu of asolid racket frame.

Figs. 5 and 6 detail a modified frame overlay of the laminated type.

Fig. 7 fragmentally represents a laminated racket frame provided withanother style of decorative overlay.

An outstanding requirement in obtaining a socalled brilliant or brightdye shade in distinctive colors, resides in maintaining the naturalwhite or the like pale color of the sapwood (alburnum) portion of ash,or the like'hardwood species against scorching without substantialdarkening by chemical changes; also in not allowing the treated woodfibers to become embrittled or brash to an extent that will seriouslyimpair the shock resisting qualities and durability thereof underfatigue loading, nor to otherwise substantially affect the wood life forsubsequent close bending particularly as applied to racket purposes.Incipient stages of decay induced by excessive temperature, are usuallyaccompanied by a visible discoloration and may cause heat treated woodto undergo pronounced permanent weakening under impact loading. Suchimpairment is augmented in a proportionate relation to excessivetemperature exposure, wood being increasingly injured with a prolongedheat treatment, whether applied during the dyeing or the drying steps.That is to say, the resulting loss in bending strength is accumulativeand tends to progressively darken the natural sapwood color by suchscorching effects to a point where the dyed colors of a lighter shademay be obliterated by a darkened background and thus materiallyneutralize or otherwise vitiate certain color effects herein sought.

In order to secure adequate penetration at a rapid productive rate thatwill produce a uniformly distributed, non-Streaky coloring in hardwoods, I preferably but not necessarily resort to a hot dye bath heldunder pressure but limit the exposure thereof to relatively hightemperature for a restricted period that will not seriously impair itstoughness to shock nor allow its initial pale shade to become darkenedsufiiciently to overpower the particular anilin dye or some otherbrilliant coloring agency such as scarlet, canary, Copenhagen blue,emerald green or the like spectral hues, in which it is moreparticularly intended to dye my bent wood frames.

As as exemplification of a preferred procedure, the following treatmentsecures the results herein contemplated. Selected white ash sapwoodstock may initially be cut into relatively long strips having across-sectional thickness of about as suitable for making an unlaminatedtennis racket or snow shoe frame of which the grain runs lengthwisewithout abnormal diagonal slope.

A large batch of such strips, stacked in spaced relation may then be setupright on end and immersed in a brilliant dyeing solution held underpressure in a closed jacketed container (preferably porcelain lined andfree from the presence of iron or other metallic element likely toaffect the dyestuff). The wood should be reasonably dry before immersionsince excessive moisture content tends to resist color absorption. Saidaqueous bath preferably contains a water soluble anilin dye of thecharacter previously indicated and said wooden strips may underfavorable conditions, be initially heated in such solution by steam orother means to about 250 for less than one hour's time, it being evidentthat the stipulated temperature may be raised lowered within reasonablelimits, depending upon the particular dyestuif employed and the intendeddyeing rate.

Thereafter, the steam may be shut off from the digester and air at apneumatic pressure at about 60 to 70 lbs. gage is maintained on the topof such hot or steaming solution for a subsequent period of some two tothree hours to hasten the dyeing process without need of fresh steam,whereupon all the processed wooden strips become impregnated to asubstantially uniform shade. My initial steam heating suffices tomaintain the dye bath at an elevated temperature with respect to theatmosphere until the color processing is completed. If desired, theusual pre-vacuum process may also be resorted to in facilitating dyeimpregnation, but this is not essential.

In attempting to color a batch of ash strips in a brilliant spectralhue, the hot dye bath should not be allowed to act for an unduly longperiod otherwise the bending strength of the dyed wood is likely tosuffer material impairment. The treated wood 'body first becomessuperficially penetrated by the dye and finally reaches saturation,whereupon it is preferred to terminate the dyeing operation by removingsaid strips from the closed container. Should the hot dyeing especiallyabove 212 F., be unduly prolonged, the tendency is first tosuperficially scorch the wood toward a dull brown shade which withcontinued excessive processing creeps inwardly and finally becomesdiffused over the whole cross-sectional profile of a dye treated woodenstrip so as to dominate the desired color shade.

While in a water saturated state, such pliant and brightly colored ashstrips may individually be sharply bent without substantial fracture andretained about a suitable forming fixture to dry thereon into a loopedtennis racket frame represented in Figs. 1 to 3. In this illustrativeembodiment, a solid frame member Ill after being dried and set, is givena closed hoop shape having the respective strip end regions extendedinto substantial parallelism to constitute an integral handle l2. Thesame style of frame may also be laminated in multiple plies or slats asindicated in Fig. 4.

The crotch portion of such racket hoop may be provided with an inlaidtriangular throat piece l3 that is glued or otherwise bonded in place.It is preferred to sectionalize said throat piece into three bondedcomponents including a dividing wooden center spline I3A which lattermay be distinctively dyed in a brilliant color shade that contrasts withthe adjoining components to constitute a characteristic emblem by whichto identify my decorative rackets to the purchasers thereof.

Such frame structure may be further fortified by a glued crescentreenforecement l4 and by separate flat overlays such as l5 or I5A buteither type of overlay may be extended into unitary formation as in Fig.'7. Each opposed handle side face or pallette may have one or morereenforcing layers or plural cheeks l6 glued thereon in superimposedrelation to enlarge the handle girth and to enhance its decorativedisplay. The closed hoop perimeter may be drilled in multiple to threadthe interwoven web strings ll therethrough.

After the aforesaid dyed frame strips have respectively been bent intohoop shape, they may be transferredv intoa kiln or the like agency tohasten the drying thereof while still mounted and held around a separateforming fixture, care being taken not to overheat such bent frames so asto avert honeycomb and cell collapse, also to prevent abnormaldiscoloration of the treated wood or the dyeimpregnation thereof. Brightanilin dyes when exposed to high temperature for a prolonged period,tend to go over into a darker shade and it is the present aim to obviatesuch color degeneration by suitably controlling my processing time andtemperatures. When too rapidly kiln or oven dried, opposed side faces ofthe treated frame strips are by abnormal core shrinkage, likely to sinkinto a cupped formation which may interfere with tight gluing,especially as regards superimposed fiat plies or veneer reenforcements.

Said kiln drying or oven baking is preferably carried out by starting ata comparatively low temperature at high humidity and, then graduallychanging over to a maximum temperature not in excess of 200 F. at arelatively lowered humidity. The accelerated drying process usuallyrequires some 12 to 24 hours after which the set bent frames may betaken out of the kiln at a moisture content somewhat below 6 to 8%. Whenseasoned to atmospheric condition, the removed frameis made ready tohave a throat piece and overlays applied thereto by a suitable adhesivesuch as animal or casein glue.

In the event flat shoulder overlays or handle layers are provided, theymay be dyed and kiln dried in accordance with the same processprescribed for the frame strips after which they may be applied intoplace. If preferred, a group of my potential frame making strips mayinitially be dyed and bent up as a whole in boardlike formation, whichis subsequently cut into sepa-- rated racket forming units.

By my refined treatment, undue darkening of the treated wood is notallowed to occur and this in turn, correspondingly prevents seriousdeterioration of the shock absorbing qualities of a bent racket frame orthe like ball impelling implement. When so restricted, the heat treatedwood stock is not subjected to sufficient darkening to vitally interferewith the application of brilliant dye of a pale shade. The use of airpressure in following up .the initial steaming, tends to preserve theoriginal pale shade of heat treated wood stock. While the use of lowerthan stipulated temperatures would prolong the process somewhat, theprescribed treatment has been found to afford a commercially useful bentwood frame that retains a high degree of its original strength.

The use of dissimilar species of more costly wood plies possessingcontrasting natural colors, is not so well adapted to fulfill exactingframe specifications in so far as their relatively lower intrinsicstrength and diverse higher shrinkage properties are not of the samefavorable character as those afforded by less costly ash, nor can thesame brilliant decorative effects be achieved'in natural colored woods.

As a result of extensive comparative tests, I have determined that ashracket frames after being dyed, bent and dried, may be upheld tosubstantially the same inherent strength possessed by a correspondingundyed ash frame. Plywood when processed in accordance with the hereinprescribed dyeing treatment, is further found to enhance both thehardness and rigidity over an undyed frame of equal size. The somewhatgreater hardness attained in a laminated frame after dyeing, protectsits impregnated pattern against wear and tear, while its augmentedrigidity reduces frame warpage when subjected to a high initialstringing tension.

Under favorable circumstances, heart-wood or fill . tain of such dyedplies.

duramen may be treated by a process similar to that described, but insuch event the final color may be expected to become somewhat darker inshade than the natural wood. Heart-wood is inherently difiicult topenetrate uniformly but such dye distribution may be facilitated bycutting the wood into relatively thinner slats to more adequatelysurface the same. Colored slats of this kind may be glue assembled intolaminated plywood in the Fig. 4 manner and then bent up into nested hoopshape.

In practice, after having cut ash boards into solid frame strips whollyof either sap-wood or of heart-wood, there remains a certain amount ofscrap which may be utilized by further cutting the same into relativelythin slats. Such surplus material may likewise be dye treated in theprescribed manner and worked up into laminated racket frames 11 of whichadjacent nested plies may be given harmonizing or contrasting colors. Ifdesired, an inlay of thin basswood, poplar, birch or the like in eithertheir natural state or in an artificially colored condition, maylikewise be incorporated and glued between cer- When difierent plies ofsuch laminated wood are to be contrastingly dyed, each color requires aseparate bath. By virtue of such treatment, the distinct hues of mylaminated frame present a sharp demarcation therebetween without need ofany interposed inlays.

In a like manner, the throat overlay ISA may be laminated around thecurvature axis ill of the bent frame in the nested fashion indicated indotted outline in Fig. 1 and worked up into diiferent colors tocorrespond in matched registry with the plies exposed along one frameside face. In such event, diversely colored segments of my unitarycrescent shaped overlay may be bent up from straight stock and otherwisetreated in a manner essentially similar to the process hereinbeforeprescribed. Inset strips of colored wood, fiber board or the like may beinterposed between the overlay plies to heighten the trim thereof.

It will be obvious that a laminated overlay such as ISA may be extendedinto a bridge piece arranged to span the forked crotch region of thelaminated racket frame II in the Fig. 7 fashion. In this instance, theplywood frame comprises nested slats A, 25B, etc., that may be spaced bythin dyed inlays such as 26. These slats are preferably dye impregnatedin distinctive spectral hues constituting a striking decorative frametrim that is primarily centered in its hoop shape and handle neck region29. The crotch region of such frame may have a throat piece 21 bondedtherein. The slat end portions again extend outwardly away from suchforked crotched region into an integral handle member 28 of which theinterposed neck region is preferably contracted with respect to thegirth of the handle grip portion. be superimposed to cover a side faceportion of the throat piece and to span the respective forked regions ofthe bent slats 25A, 253, etc., as shown, said overlay being laminated inupstanding edgewise registry with corresponding underlying slats inmatched color scheme to virtually complete a series of endless bandsarranged concentrically about the axis l8 and thereby enhancingly alterthe embellishment afforded by the aforesaid color trim.

By these means, it becomes possible to achieve strikingly beautifuldecorative effects and overlay modifications thereof as, applied toracket An ornamental overlay such as 30 may purposes not heretoforeattainable in natural wood colors. As an illustration, a de luxelaminated frame comprising adjoining ash piles may be .dyed in delicateharmonizing light and dark shades of a preferred color such as eitherblue, green or red, and when such different tones of a single brilliantcolor are assembled, they provide for an exceptionally attractive racketadornment that will not wear ofl. Complementary thereto, a series ofhandle reenforcing cheeks such as l6 may be similarly dyed to impart acontrasting or harmonizing color scheme thereto, the respectiveoverlapping forward cheek edges as at "5A then being preferably steppedand beveled to simulate a quarter sawed eifect.

As a further variant, a flat overlay such as 20' may also be applied tothe side face of a racket frame. As separately detailed in Figs. 5 and6, such overlay may be laminated flatwise and have certain pliesartificially dyed in different colors that respectively extendthroughout the length of such plies, the tips thereof as at 2| againbeing overlappingly disposed in the manner stipulated for the handlechecks I6A.

It will be obvious that my combined wood treatment may also be practicedin a reversed order to accomplish the same result by first bending suchstock and then dyeing the same, all required steps including kiln or airdrying of the product being completed without allowing the dyed wood tobecome materially darkened to an extent that will vitiate the sought formatched color shade.

In the case of dyeing heart-wood to a mahogany or the like darker color,the anilin dye bath and length of total heating treatment must still beproperly controlled for present purposes in order to counteractsuperficial discoloration by scorching and not allow the dye bath byleaching to go off color to a different shade while treating such wood.For instance, when dyeing a racket frame to a delicate brown color tone,the steaming temperature should be duly limited as to processing time toinsure a predictable color result capable of being consistently andregularly reproduced on a rapid scale to a substantially identicalshade, particularly so where the dyeing of such article is to berepeatedly held to a given delicate dark color tone. By deeplyimpregnating a racket frame as described, its surface color may bepermanently maintained without pronounced fading or tendency of beingabsorbed inwardly into an underlying non-colored core stratum.

The foregoing is descriptive of a commodity that has been entirelysatisfactory in practice as applied to the manufacture of attractivelycolored frames of bent wood, and which specification when read inconnection with the accompanying drawing, is believed to make apparentto those skilled in this art, the advantages afforded by myimprovements, it being understood that the more novel features thereofare subject to considerable latitude in execution, all without departingfrom the spirit and .scope of my invention as defined in the appendedclaims.

} I claim:

1. A laminated wooden frame assembled to include nested plies of one andthe same species of wood that are bent into a common arcuate shape andglued together into a unitary structure of which certain plies are dyeimpregnated in distinctive artificial colors prior to the gluing thereofand whereby ply rigidity is augmented with respect to the similarproperty originally possessed by such undyed wood species.

2. A unitary implement of laminated wood comprising nested plies thatare similarly bent and glued together into a given arcuate shape,certain of which plies prior to the gluing thereof are respectivelyimpregnated with a water soluble anilin dye throughout their respectivebody confines in distinctive hues.

3. A unitary impelling implement including a dye impregnated bent frameof wood stock that is given a hoop shape having its respective terminalsdisposed in substantial parallelism to provide for a handle and whichframe by the dyeing thereof is rendered somewhat more rigid than theoriginal wood stock prior to the dyeing thereof, and a web strung tospan the hoop shaped portion of said frame.

4. An embellished impelling implement having a frame. of laminated woodstock including a pair of plies that are similarly bent and gluedtogether flatwise in nested relation, each such assembled ply prior tothe gluing thereof being impregnated with a different soluble syntheticdye 26 stuff to impart distinctive artificial colors throughout therespective plies thereof and which plies by the dyeing thereof are in acomparable dried state augmented in superficial hardness with respect tothe same property originally possessed by the wood stock and renderedmore resistant to superficial abrasive wear without material injury tothe original toughness quality possessed by said stock.

5. An embellished laminated racket frame including a pair of nestedwooden slats that are similarly bent and glued fiatwise into a hoopshape including a forked crotch region from which the several slat endsextend outwardly into a common handle having an interposed con tractedneck region, corresponding exposed edge portions of said pair of slatsbeing respectively dye impregnated in distinctive artificial colors toprovide a decorative color trim for said frame, and an ornamentaloverlay of dyed-wood fixedly superimposed upon the aforesaidcorresponding exposed slat edges in the vicinity of said crotch regionand which overlay is laminated in matched upstanding edgewise registryalong a length portion of such underlying slat edges, said overlayleaving a dye impregnated edge portion of the hoop shape uncoveredwherebyto enhance the embellishment afforded by said color trim.

6. A unitary implement including a dyed-wood frame member bent into ahoop shape providing for a crotch region, an inlaid throat piece bondedinto said crotch region, and a dyed-Wood overlay fixedly associated withsaid throat piece, said overlay being cross-sectionally laminatedradially around a curvature axis of the hoop shape and having thelaminations thereof directed in. substantial parallelism with such axis.

'7. A unitary ball impelling frame of laminated wood comprising benthoop shaped plies glued together in nested relation, certain of whichplies prior to the gluing thereof being respectively impregnated withsoluble synthetic dyestuff in distinctive artificial coolrs.

8. An embellished hoop shaped frame fabricated from bent wood stock tocomprise nested laminations that are glued together, one of such woodenlaminations prior to the gluing thereof being impregnated with solublesynthetic dyestuif to produce an artificial color that is distinctivefrom its natural color.

97 An embellished racket frame or the like hoop shaped structureprovided with an integral handle, said frame comprising gluedlaminations of bent wood that respectively extend lengthwise of the hoopforming frame portion in nested relation to terminate in the handlethereof, at least one such wooden lamination prior to the gluing thereofbeing impregnated with soluble synthetic dyestufl'.

WILLIAM C. WHYTE.

